Abrasive cutoff machine



Feb. 18, 1941. 5 HARDY 2,232,387

ABRAS IVE CUTOFF MACHINE Filed June is, 1958 A T TORNEY.

Patented Feb. 18, 1941 ABRASIVE CUTOFF MACHINE Benjamin G. Hardy, Merchantville, N. J., assignor to A. P. de Sanno and Son, Inc., a corporation of Pennsylvania Application June 13, 1938, Serial No. 213,379

'4 Claims.

My invention relates to cutting metal and relates particularly to cutting through metal of considerable cross-sectional area.

Heretofore, it has been customary to cut metal by means of an abrasive cutting disc which is thin and rotatable at a high rate of speed. In the prior art devices it has been customary to hold the stock stationary and move the rotating cutter into direct contact with the metal so that the metal is cut in one sweep of the rotatable blade. However, in the use of this method there is a large arc of contact between the metal and the cutting edge of the rotatable cutter and there is danger of burning the metal, and when there is burning of the metal it necessitates the cutting away of that burnt metal. When a deep cut is made by the abrasive wheel a tremendous amount of energy is required to rotate the wheel.

Heretofore wheels of resinoid bond or Bakelite wheels could not be used successfully in the wet cutting of metal. This is apparently due to the resinous bond in the wheel which forms a glazed surface on the edge of the cutting disc and provides a burnishing surface rather than an abrasive surface.

It is, therefore, an object of my invention to overcome the difficulties aforementioned by providing a machine wherein resinoid bondedabrasive wheels may be successfully used by the Wet cutting of metal.

Another object of my invention is to provide an abrasive cutoff machine in which the arc of contact of the stock with the cutting disc is being comparatively changed at frequent intervals. r

Another object of my invention is to provide an abrasive cutoff machine wherein. an abrasive disc of smaller diameter than those heretofore used may be used.

Another object of my invention is to provide a cutoff machine wherein the power consumption is relatively low.

Other objects of my invention are to provide an improved device of the character described, that is easily and economically produced, which is sturdy in construction and which is highly efficient in operation.

With the above and related objects in view, my invention consists in the following details of construction and combination. of parts, as will be more fully understood from the following description, when read in conjunction with the accompanying drawing, in which:

Fig. 1 is a perspective view of another modification of my invention.

Fig. 2 is aside elevational view of the pawl and ratchet stock rotating unit.

Fig. 3 is a fragmentary sectional view of the unit shown in Fig. 2.

A spray of water for cooling purposes may be projected upon the abrasive wheel A if it has a resinoid bond or if it is a Bakelite wheel when the wheel is employed to cut through heavy metal of a diameter greater than two inches. Heretofore, where a single cutof the metallic stock was attempted by a resinoid bonded wheel it was found that such wheel would not cut through heavy stock. It ismy theory that under such circumstances of cutting heavy stock'the and the rotatable cutter A are continuously moving the cutter need only pierce one-half the diameter of the stock whereas when the stock is held stationary the cutter must pierce the entire diameter of the stock; Thus, the cutter can be used for a longer period of time when the stock rotates or as a corollary a smaller diameter abrasive cutter may be*used when the stock is rotated as compared to the time when the stock is held stationary.

Referring to a modification of my invention I show in Figs. 4, 5 and 6 a cutoff machine wherein the stocks to be cut by the abrasive cutoff wheel A is rotated in an intermittent manner, to Wit: the stock is oscillated in one direction, the stock is oscillated in the reverse direction at a less arcuate distance than the first arcuate movement, the sto ck is oscillated again in the first direction an arcuate distance equal to the first direction, then the second reverse arcuate movement occurs with these reversals of the stock continuing until the stock is severed and it should be apparent that the net movement of the stock is in a rotary direction.

The mechanism by which the hereinbefore oscillatory-rotary movement is effected consists of a rotatable stock holder, generally designated as D, Figs. 1, 2 and 3, wherein a pair of ratchet wheels 90, 92 spaced apart by an actuating lever 94. The ratchet wheels 90 and 92 have the teeth on the periphery thereof face in opposite directions in order that the stock S may move or be moved in opposite rotary directions. In other words, ratchet 92 enables the stock S to be rotated clockwise as Fig. 2 is viewed and ratchet 90 enables the stock S to be rotated counterclockwise as Fig. 2 is viewed.

Complementary to ratchet wheel 90 is a spring pressed, pivoted detent, pawl or click, generally designated as E, which has a tooth engaging end 96 and a cam end 98. The cam end 98 of the pawl E is adapted to raise the tooth enga ing end 96 after the: operating lever 94 has oscillated, by virtue of the cam surface I00 riding against a pin I02, which may be fixed or optionally set at any predetermined distance to limit the teeth engaging stroke of the pawl E.

A spring pressed pawl I04 engages the teeth of ratchet wheel 92. Both pawlsE and I04 are pivotally mounted upon the operating lever 94.

A description of the operation of the invention illustrated in Figs. 1, 2 and 3 will best describe the elements and their cooperative function hereinbefore set forth. The stock S is locked in the chuck of the cutoff machine D. The abrasive cutter is in position to cut the stock and the pulley 3| is rotated, the belt 39, the pulley 34 and wheel 32 are also rotated by virtue of these connections, with the link I0 oscillating the lever arm 94. As arm 94 moves downwardly the pawl I04 engages the teeth of ratchet wheel 92 and moves the stock S clockwise-after the end of the stroke of lever 94 has been reached the cam surface I00 is in engagement with pin I02, thus raising the tooth engaging end 96 of pawl E and for a limited portion of the return stroke the stroke S is stationary. After the cam surface I00 is out of engagement with the pin I02 the pawl end 96 engages the teeth of ratchet wheel moving the stock counterclockwise, meanwhile the pawl I04 slides over the points of the teeth and will be ready to push the ratchet wheel 92 on its downward motion as before.

Clicks or pawls which pull may supplant those clicks which push.

It is to be noticed that the net result of a complete oscillation of the arm 94 is a clockwise movement of the stock.

With repeated oscillations of the arm 94 the stock oscillates back and forth varied distances with a net circular movement of the stock when a sufiicient number of oscillations has occurred.

Thus, using a cutoiT machine as described herein the abrasive wheel cuts the stock in short strokes and only goes to the center of the stock before the cut is completed.

It is also within the scope of my invention to use rubber bonded abrasive wheels for cutting the metal stock.

Although my invention has been described in considerable detail, such description is intended as illustrative rather than limiting, since the invention may be variously embodied and the scope of the invention is to be determined as claimed.

I claim as my invention:

1. A method of cutting through heavy stock comprising the steps of rotating an abrasive wheel, moving said wheel in contact with the stock to be cut, moving said stock in one direction, reversing the movement of said stock a less distance of said first movement, and repeating the oscillation of said stock as hereinbefore set forth.

2. A cutoff machine comprising a thin rotatable cutofi wheel, a stock holder, means to oscillate said stock a predetermined amount in one direction, and means to oscillate said stock a different predetermined amount in the reverse direction.

3. A cutofi machine comprising a thin rotatable cutter of abrasive material, a stock-holder unit, said stock-holder unit being rotatably mounted, a plurality of ratchet wheels on said rotatable member, each of said ratchet wheels having the teeth spaced in opposite direction, an actuating member attached to said stockholder unit, a plurality of pawls, each of said pawls cooperable with each of said ratchet wheels, means whereby one of the pawls will engage its complementary ratchet wheel as the pawl is moved in a definite direction whereby it may actuate the ratchet wheel, means whereby another pawl will engage its complementary ratchet wheel in order to reverse the direction of movement of said stock-holder, and means whereby one of said pawls will be in engagement contact with its complementary ratchet wheel to move the work holder unit a less degree of rotation than the other pawl and ratchet wheel.

4. A cutofi machine comprising a thin rotatable cutter of abrasive material, a stock-holder unit, said stock-holder unit being rotatably mounted, a pair of ratchet wheels on said rotat able member, said ratchet wheels having the teeth spaced in opposite direction, a pair of pawls, each of said pawls cooperable with each of said ratchet wheels to move the stockholder unit in one direction, the other pawl having a cam end formed therewith and cooperable with the other ratchet wheel whereby the stock-holder unit will be moved in the direction opposite to that of the other movement of the other ratchet wheel, means whereby the cam end of the other pawl will be lifted from engaging its complementary ratchet wheel so that no motion of the ratchet wheel occurs as the other pawl is moved in the direction in which it may ordinarily actuate the ratchet wheel, an operating lever adapted to move each of said pawls and said ratchet wheels, said means to lift said pawl from its complementary ratchet wheel comprising a pin and the cam and on one of the pawls, and said pin adapted to be fixed or optionally set at any predetermined distance to limit the teeth engaging stroke of the pawl engaging said pin.

BENJAMIN G. HARDY. 

